U.S. patent number 4,104,709 [Application Number 05/786,283] was granted by the patent office on 1978-08-01 for surgeons headlight with continuously variable spot size.
This patent grant is currently assigned to Applied Fiberoptics, Inc.. Invention is credited to Jacobus Kloots.
United States Patent |
4,104,709 |
Kloots |
August 1, 1978 |
Surgeons headlight with continuously variable spot size
Abstract
A surgeon's headlight utilizing an adjustable iris diaphragm to
allow continuous variation of the diameter of the illuminated
spot.
Inventors: |
Kloots; Jacobus (Sturbridge,
MA) |
Assignee: |
Applied Fiberoptics, Inc.
(Southbridge, MA)
|
Family
ID: |
25138161 |
Appl.
No.: |
05/786,283 |
Filed: |
April 11, 1977 |
Current U.S.
Class: |
362/105; 362/282;
362/321; 362/804; 600/249 |
Current CPC
Class: |
F21L
14/00 (20130101); F21L 15/02 (20130101); F21V
11/10 (20130101); G02B 6/0008 (20130101); Y10S
362/804 (20130101) |
Current International
Class: |
F21V
8/00 (20060101); F21L 14/00 (20060101); F21V
11/00 (20060101); F21V 11/10 (20060101); F21C
015/14 () |
Field of
Search: |
;128/20
;362/105,255,280,282,321,804 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Nelson; Peter A.
Attorney, Agent or Firm: Tarrant; Thomas N.
Claims
I claim:
1. A surgeon's headlight for providing a variable diameter
illuminating spot comprising:
(a) a lamp housing;
(b) means to secure said housing to a headband;
(c) a fiberoptic cable receptacle in said housing;
(d) a fixed entrance condenser lens following said receptacle in
said housing;
(e) a variable iris proximate said entrance condenser lens in said
housing;
(f) a fixed exit lens following said iris in said housing arranged
to image said iris in a field 25 to 45 cm in front of said housing;
and,
(g) manipulatable means connected to said iris and extending
through said housing for varying the aperture of said iris, said
condenser lens having a configuration and position to provide
magnification of the exit pupil at said receptacle so as to
illuminate the entire entrance surface of said exit lens, whereby
changing the diameter of said iris will change the diameter of an
illuminated spot without changing illuminance.
2. A surgeon's headlight according to claim 1 wherein said housing
comprises a substantially vertical section holding said entrance
condenser lens and a substantially horizontal section holding said
exit lens and optical means are included in said housing for
redirecting light from said condenser lens through said exit
lens.
3. A surgeon's headlight according to claim 1 wherein the entrance
surface of said condenser lens is spaced within 7 mm of said
receptacle.
4. A surgeon's headlight according to claim 1 wherein said
condenser lens is a plano-convex doublet.
5. A surgeon's headlight according to claim 4 wherein said exit
lens is a plano-convex doublet.
6. A surgeon's headlight according to claim 1 wherein said iris is
positioned within 3 mm of said condenser lens.
7. A surgeon's headlight according to claim 1 wherein said housing
has a manipulating handle attached at its forward end and in line
with said manipulatable means, said handle serving to adjust the
position of said housing for directing said illuminating spot.
8. A surgeon's headlight according to claim 1 wherein a change in
the diaphragm aperture of said iris of 1 mm to 12 mm produces a
change in the illuminating spot 36 cm from said lamp of 10 to 75
mm.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to surgeons headlights, and
particularly to such headlights utilizing fiberoptic cables to
introduce the light from a separate illuminating source.
2. Description of the Prior Art
In recent years, headlights used by surgeons and for other medical
and dental purposes have become greatly reduced in size and weight.
A principal factor in size reduction has been the use of flexible
fiberoptic cables to carry the light from a separate light source.
U.S. Pat. No. 3,951,139 of the present applicant discloses an
example of such a headlight. With these small headlights it is not
easy to allow for adjustment of the optical components to vary the
size of the illuminating spot.
When a surgeon is trying to operate within a very small cavity, an
illuminating spot larger than the cavity opening results in a
substantial amount of undesired reflected light. This light reduces
the visibility of the objects of surgical interest, since too much
of the return light does not carry the visual information desired.
If the illuminating spot can be reduced in size so that only the
cavity interior is illuminated, the surgeon's viewing is greatly
improved. Nevertheless, surgeon's headlights today generally have a
fixed spot size. In some cases a dead black cloth is utilized
around the operating aperture to absorb the unwanted light.
SUMMARY OF THE INVENTION
The present invention provides a surgeon's headlight producing an
illuminated spot of which the size can be varied continuously
between wide limits. A fiberoptic cable entrance brings light to
the device; a diaphragm selects the part of the incoming lightbeam
that will be used, and an exit lens system images the diaphragm
onto the object to be illuminated. This results in a system where
variation of the diaphragm aperture varies the size of the
illuminated spot. Additional entrance optics close to the diaphragm
help to keep the illuminance constant while the spot size is varied
by imaging the light source (exit face of fiberoptic cable) on the
entrance surface of the exit lens system.
Since this arrangement is essentially masking off part of the
light, undesired heat generation in the headlight might be
expected. Fortuitously, the light reaching the headlight in modern
fiberoptic headlight systems is very low in thermal energy. The
longer light wavelengths are highly attenuated in the cable and
usually by additional filtering at the source. Thus heat resulting
from the iris is minimal.
The headlight of the invention is provided with a projecting
"joystick" on top of the lamp unit for changing beam direction and
a projecting knob behind the joystick provides variation of spot
diameter by rotation about the optical axis. Thus both spot
diameter and beam direction are readily adjusted.
Further objects and features of the invention will become apparent
upon reading the following description together with the
drawing.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a cross-sectional view of one embodiment of the
invention.
FIG. 2 is a cross-sectional view taken along line 2--2 of FIG.
1.
FIG. 3 is a cross-sectional view of a second embodiment of the
invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT:
A surgeon's headlight, according to the invention, necessarily
comprehends a headband, a light source and a fiber-optic connecting
cable from the light source. The present description however only
describes the light itself, since the other components are
conventional in the present state of the art.
Light 10 is depicted in FIG. 1 with a body made of housing 11.
Housing 11 is suitably a metal die casting or a plastic molding.
Integral with housing 11 is arm 14 extending outward and
terminating in ball 14. Ball 14 is designed to mate with a ball
socket mounted to a headband so as to provide an adjustable ball
and socket joint.
Extending from the front top of housing 11 is handle 15 which
serves in the manner of a "joystick" for adjusting lamp 10 in the
ball and socket joint (not joint). Coaxially at the rear of housing
11 is receptacle 16 for a fiberoptic cable (not shown). The
interior of housing 11 is hollow and following receptacle 16 toward
the front of housing 11 is condenser lens 17. The purpose of lens
system 17 is to collect light efficently from the source and apply
the correct magnification to fully illuminate the exit pupil. A
combination of two plano-convex lenses back to back (plano-convex
doublet) such as depicted, is commonly used for this purpose. Thus
lens system 17 provides an enlarged image, of that plane in
receptacle 16 where the exit surface of a fiberoptic cable would
lie, upon the entrance surface of lens system 24.
Immediately following lens system 17 is iris 18. Iris 18 is
suitably the conventional interleaved iris assembly found in
cameras and a large variety of other optical equipment for control
of light intensity. Iris 18 is operated by knob 20 projecting
through housing 11 and connected inside housing 11 to ring 21. Ring
21 is coupled to the leaves or iris 18 so that rotation of ring 21
causes iris aperture 22 to open and close in conventional
fashion.
Following iris 18 and located at the front of housing 11 is exit
lens 24 which also serves as the exit pupil of the headlight. Lens
24 is depicted as a second condenser lens system of the
plano-convex doublet style. In the depicted embodiment, lens 24
serves to image iris 18 at the plane to be illuminated. For medical
purposes it has been found desirable to have an illuminated spot
diameter variable from about 15 to 75 mm. at a distance of about 25
to 45 cm.
The characteristics of lens system 17, and its position relative to
the fiberoptic cable and the other optical components of the
headlight must be chosen such that, no matter how the diaphragm is
adjusted, no part of lens 24 remains unilluminated. This is
accomplished by using lens system 17 to image the exit face of the
fiberoptic cable in the plane of the entrance face of lens system
24. As a matter of design, it is preferred to have iris 18 as close
as convenient to the exit surface of lens sytem 17. The iris 18 is
imaged by lens system 24 into the plane to be illuminated. If the
size of the iris aperture is varied, the size of the illuminated
spot varies accordingly. As the exit face of the fiberoptic bundle
is not imaged into the plane of the illuminated spot, the granular
structure of the exit face of the fiberoptic bundle is not at all
visible in the illuminated spot. The illuminance in the spot (i.e.
the lightflux measured per unit of area) is independent of the
diaphragm setting, because the aperture of lens 24 remains fully
utilized when the iris size is reduced.
Referring to FIG. 2, it will be seen that knob 20 rides in slot 25
which restricts its maximum rotation. In the depicted embodiment,
knob rotation is restricted to approximately 90.degree. giving an
iris aperture variation of 1 mm to 12 mm.
FIG. 1 shows a headlight with the optics arranged coaxially in a
straight line. FIG. 3 illustrates an alternative embodiment
providing a 90.degree. bend. The same reference numerals are used
in FIG. 3 as in FIG. 1 for designating identical components.
Housing 30 has a vertical section 31 housing receptacle 16,
condenser lens 17 and iris 18. Horizontal section 32 of housing 30
carries lens 24 and joystick 15. At the rear of setion 32 is
integral protruding flange 34 with aperture 35 for mating in a
swivel connection with a like flange from a headband (not shown).
Rear wall 37 of section 32 is inclined at a 45.degree. angle and
supports reflector 38 on its inner surface. Reflector 38 is
positioned centered with the optical axies of both lens 17 and lens
24 for bending the optical path through a 90.degree. angle. Other
devices such as prisms may be used equally for the same
purpose.
Outside of the reflector and angular construction, the lamps of
FIGS. 1 and 3 can be essentially identical. The construction of the
FIG. 3 embodiment places knob 20 directly behind and close to
joystick 15 permitting simultaneous adjustment of spot size and
direction. Table I gives exemplary dimensions for the embodiment of
FIG. 1, most of which can also be applied to the embodiment of FIG.
3.
TABLE I ______________________________________ Spot size at 36 cm
10 mm to 75 mm Iris diaphragm (18) opening 1 mm to 12 mm Lens 17
diameter 15 mm Receptacle 16 I.D. 7.5 mm Lens 24 diameter 30 mm
Space between receptacle 16 and lens 17 7 mm Space between entrance
surfaces of lenses 17 & 24 55 mm Magnification of exit pupil
from recepta- cle 16 at entrance pupil of lens 24 5 Magnification
of exit pupil from recepta- cle 16 at 36 cm from light 45 Space
between iris 18 and exit of lens 17 1.5 mm
______________________________________
Many variations are contemplated as within the invention. For
example optical angles other than straight and 90.degree. can be
used. Exit lens 24 can be replaced with a simple plano-convex lens
with a small loss in optical quality. The means for mounting to a
headband is not critical and any of the various known mounting
means may be utilized. Nor is the system aperture at any point
critical. The particular pupil sizes are selected as a matter of
design for the particular performance desired as is the
magnification of the optical system. Thus it is intended to cover
the invention as set forth in the following claims.
* * * * *